This paper invites scholars interested in science-religion
relationships to examine the notion of "levels of
explanation" in more depth than is usual. Interactions among
epistemological and ontological aspects of levels have been explored in writings
about "hierarchy theory." Examples of expanded levels ideas
are considered in three areas: evolutionary biology, molecular biology, and
epistemology. These examples suggest that connections between ontological and
epistemological levels are important to explore when the scope of a scientific
theory is broad enough to be reflexive, when one looks closely at a boundary
between levels, or when one considers connections between scientific and
religious knowledge.

In recent years the pages of this journal have carried several discussions
highlighting some key concepts for understanding science-religion dialogue,
including reflexivity, complementarity, and levels of explanation (e.g., Cramer,
1985; Haas, 1983; Van Leeuwen, 1983). While these concepts are closely
interrelated, emphasizing one of them for discussion is much more manageable
than trying to sort them all out at once. My aim in this paper is to support
this clarification process by looking further at the notion of "levels
of explanation." In particular, I examine literature from an
interdisciplinary area of study sometimes referred to as "hierarchy
theory" because it is one valuable resource for
clarification.1

Levels of explanation and related notions often hold pivotal positions in
discussions of religion and science relationships, particularly among scholars
seeking to demonstrate the compatibility of the two domains (e.g., Barbour,
1966; Bube, 1971; Capra, 1982; MacKay, 1979; Peacocke, 1986; Polkinghorne,
1986). Despite the popularity of levels notions in the exploration of
science-religion interfaces, there are many unanswered questions regarding the
viability of current formulations (e.g., Cramer, 1985; cf. Orlebeke, 1977). In
fact, there also are unresolved questions in the broader literature on "hierarchy theory," so the open-endedness of levels notions
in religion-science discussions is not surprising (Pattee, 1973; cf. Grene,
1972; Salthe, 1985). Moreover, since concepts of a hierarchy of levels have a
wide-ranging history in both Western and Eastern intellectual traditions (e.g.,
Capra, 1982; Leake, 1969), it is probably unrealistic to expect coherent,
consistent use of these ideas across diverse areas of study. In this paper, I
explore a selected set of questions in hierarchy theory to highlight potential
directions for fruitful development of hierarchy models. A next step, applying
these issues to science-religion dialogues, is the task of a companion paper.

Background Terminology

Given the diversity and poorly coordinated nature of literature on hierarchy
theory and levels of explanation, terminology is an important preliminary
consideration. Although the term "hierarchy" is often used
to describe authority relations in institutions or relations among taxa in
classification systems, the focus for this paper is the use of "hierarchy" to describe an ordered sequence of levels more
generally. Different kinds of hierarchies can be distinguished from the
outset.2 Levels of "explanation," "analysis,"
"abstraction," or "description" emphasize hierarchical strucuture as reflected
in knowledge systems. Epistemic concerns (i.e., concerns about the nature of
knowledge) are frequently emphasized by "levels of
explanation" terminology. Sometimes levels of explanation are
expressed as a form of the traditional "hierarchy of
disciplines" which features physics at the base, biology in the
middle, and social science toward the top (cf. Beckner, 1974). By contrast, one
can distinguish levels of "being," "reality," or "organization" as
designations for basic ontic (reality) structures, usually ¨emphasizing nested
composition patterns of elementary entities or "things." The "levels of organization" frequently used as a framework for
biology curricula is a classic illustration of compositional levels: cell,
organism, population, etc. Each level of the hierarchy is defined by things
which are composed of entities from the level below: for example, organisms are
made up of cells. Finally, one can also identify levels of "activity" or "modal aspects" which
reflect functions or processes instead of the entities in compositional
hierarchies (e.g., Barbour, 1966; Hart, 1984). For example, some authors argue
that mind-brain questions reflect different modes of functioning (physiochemical
and cognitive) of a single entity (a person) rather than reflecting different
entities (brains and minds).3 It is helpful to
note that both compositional and functional hierarchies describe reality (ontic
patterns), though functions and entities are not usually considered the same
kind of reality. Differentiation among hierarchies can easily be continued
beyond these types, but for the present purposes distinguishing epistemic,
compositional, and functional hierarchies of levels will suffice.

A central reason for clarifying and elaborating our understanding of
hierarchies of levels is to contribute to dialogue between religion and science.
Eventually, this aim will require developing insights from hierarchy theory
beyond current consensus in the field. As a beginning, however, it is important
to learn what we can from what is currently being developed. My strategy for
getting started is to focus on interconnections between epistemic and ontic
hierarchies, and to illustrate what happens when one does this. Admittedly, the
material is at times abstract, but then hierarchy theory is similar to the
interdisciplinary nature of religion-science dialogue in that it requires most
of us to be out of our depth most of the time. In reading philosophers of
science and scientists working on theory construction, I find their work
intertwines to a large degree with this area, so no attempt is made to
systematically separate various disciplinary strands in the following
discussion. My hope is that the continuity of topic justifies any blurring of
disciplinary boundaries.

To focus the discussion of interconnections between ontic and epistemic
hierarchies, I will make brief excursions into theoretical biology and
philosophy of science. In the recent history of science, biology has provided
the richest context for development of hierarchy theory. In particular,
biological ecology,4 molecular biology, and
evolutionary theory have used levels concepts in systematic theorizing. It comes
as no surprise, then, that two of the three selections overviewed in this
article focus on biological topics. First, selected issues in evolutionary
biology provide an illustration of the breadth of scope possible within
hierarchical models. A second point focuses on molecular biology as a case where
hierarchy considerations arise at a boundary between levels. Finally, a view of
epistemology is discussed to raise issues surrounding connections of
hierarchical models with social and spiritual reality. Many aspects of the
positions presented here are controversial and nothing is without challenge,
especially within the disciplines of the authors. Nevertheless, the work
considered below may be able to aid attempts to elaborate our understanding of
ontic and epistemic levels.

One set of ontic-epistemic interactions among hierarchies arises from
acknowledging the reflexivity of an observer generating a theory about an ontic
hierarchy in which the observer "fits." For example, a
biologist studying evolution can develop a hierarchical model in which humans
(including theoretical biologists) fit at an organism level. The broad scope of
evolutionary theory requires reflexive theory because the theory addresses
realities (e.g., process rates and levels of organization-see below)
which are part of the context for theory building by humans. Note that this
self-reference involves both descriptive levels of theory construction and the
compositional levels of organization. So reflexivity implies interconnections
among ontic and epistemic hierarchies. Stanley Salthe explores several issues
dealing with self-reference and hierarchy as background for his proposal of a
framework for evolutionary biology.6 To illustrate
perspectives offered by hierarchy theory, I will discuss two topics addressed by
Salthe: (a) differences in average rate of processes between levels, and (b) the
interdependence of research interests and levels of organization.

Differences in the average rates of key processes are often observed in
entities at different levels.7 This pattern has
consequences for an observer situated at a given level. Considering processes of
growth and decay, for example, the lifespan of organisms is often in a range
from one to a few generations, while the "lifespan" or
duration of biological populations extends over many generations. More
generally, from the perspective of an observer's level, processes at a
preceding, micro, or "lower" level (e.g., an atom level
preceding a cell level) are "seen" as constants. That is,
micro-level processes generate constraints reflecting the cumulation of multiple
cycles because the rates of preceding level processes are much faster than
processes at a given level of observation. For example, the temperature of
objects is not directly perceived by humans as vibratory patterns of atomic
structure, but as a molar, semistable characteristic. Interestingly,
interactions of an observer's level with subsequent, macro, or "higher" levels are also often perceived as constant
constraints, in this case because the process rate is so slow relative to the
rates of observation processes. Consider our perceptions of glacial activity; we
cannot directly perceive glacial motion.8

Since observers are "embedded" in a specific level and
average process rates differ between levels, one can see why entities at
different levels (e.g., atoms and ecosystems) can be difficult to perceive when
compared to observations of entities at the observer's level. For micro-levels,
the "thing-ness" of small entities is lost in the fabric of
events because micro-processes cumulate to act as constraints at the observer's
level. For macro-levels, entity activities are seen as constant patterns of
constraint characterizing the environment because the rates of change are slow
relative to observation level processes. Since the co-occurrence of multiple
processes is a major principle for identification of entities, rate
differentials render the identification of entities at other levels more
difficult by inhibiting the perception of processes. Using the terms presented
above, descriptive levels (for identification of entities and processes) are
intertwined with levels of organization (as reflected in the average rates of
processes) in a manner which shows up particularly in instances of cross-level
observation.9

Whatever the source of the change in perspective,
a new entity
inhabits discussion which
cannot be simply set along side of familiar things.

A closer look at how explanatory and compositional levels intertwine here
requires an examination of dynamics in hierarchical systems in which an observer
is embedded. An illustration may help clarify what Salthe is suggesting.
Consider the process of an observer overcoming the difficulties of perceiving
some target entity which is at a level other than the observer's: say, an
ecosystem. This learning process can be broken down into phases for the sake of
discussion (without implying any rigid categories or temporal ordering). At
first, the observer does not distinguish a target ecosystem from among the
variety of environmental features and the fabric of events shaping the world. In
this first phase, the observer and target interact in such a way that the target
is not clearly perceived as an entity. A forest or riverbank is seen as a place,
an undifferentiated aspect of the environment. This "observation" process reflects the average rate of processes
characterizing both the observer level and the target level. One might well see "seasons" in the forest and adjust actions like tapping the
maples for sap only in the spring. But one might not, for example, notice the
patterns which distinguish seasons in the forest from the seasons of the prairie
or mountain top. They are just different places, not systems which actively
shape the weather and climate.

In a second phase, some change in the observation and perception processes
results in a new identification of coherence. Perhaps stories across generations
about a place, a given forest, start to come together in such a way as to
encourage seeing the forest as a "living thing." Or perhaps
a field biologist identifies patterns across a number of contemporary ponds
which fit historic data for a given pond, suggesting that ponds have "lifespans,"
that they emerge, "grow, develop, and die." Whatever the
source of the change in perspective, a new entity inhabits discussion which
cannot be simply set along side of familiar things. A bear and a riverbank are
simply not the same kind of things. One develops a new level of
explanation-or fits this new entity somewhere in one's already well
developed descriptive hierarchy.

A third phase emerges when the modified levels of explanation function as a
framework for action in addition to providing a perceptual frame. Perhaps the
observer develops a new observation technology to take into account the new
understanding of phenomena related to the target. Clearly one can identify rates
of certain target processes without necessarily employing a sophisticated
epistemic hierarchy as a framework. Knowing that spring is the best time to tap
maples for sap does not require a modern ecosystems theory. Nevertheless,
coordinating actions across mutiple domains or tracing complex interactions
across wide systems often improve with the insights gained from more elaborate
models (including hierarchy structures). The helpfulness of ecosystems concepts
in tracing the deaths of maples in Quebec to acid rain serves as a case in
point.

Finally, a fourth phase involves the impact of changed observer actions on
physical reality. If a soil scientist advises a farmer, the resulting
agricultural technology, embodying relevant levels of description, may
significantly impact the interaction of the farmer with the ecosystems related
to the farm. Or a scientist developing observational technology for marine
ecosystems based on novel concepts may change the interactions of the observer
with the target, an ontic outcome of epistemic processes. Fourth phase activity
thus reflects an ontic change in the interlevel interaction between the observer
and the target. If farmer-field ecosystem interaction changes as a result of the
introduction of new herbicides or fertilizers, the ecosystem may simply adjust
to the new relationship or it may change drastically if important stability
mechanisms are disrupted. The main point here is that changes in levels of
description may lead to ontic changes, perhaps even in levels of organization if
an ecosystem transforms radically.10 Any change
might, in turn, bring us back to Phase One if relevant entities are not
perceived. Hierarchy models can help understand such processes as part of the
dynamics of hierarchical systems.

To summarize the illustration, the transition from first to second phase
described above reflects a familiar process to working scientists and "scientific realists." The intertwining of composition
levels and description levels involves ontic patterns shaping epistemic patterns
through observation. More simply, we "learn something about the world
through observing." The later transition from phase three to phase
four may be less intuitively familiar, however, in that we find our
understanding actually forming reality.11 An
observer's levels of explanation become a framework for action which results in
ontic consequences, possibly shaping levels of organization.

I have described this point in some detail because it serves to
illustrate reciprocal interactions between epistemic and ontic levels, a point
easily passed over in summary. My emphasis is on the necessity of distinguishing
between levels of explanation and levels of organization in order to formulate
claims like Salthe's. To the degree that Salthe's assertions (or disagreements
with him) make use of epistemic-ontic relations among levels, my aim of
illustrating the value of the distinction between different kinds of hierarchies
is supported.

Changes in levels of description may lead to ontic changes,
perhaps even in levels of organization if an ecosystem transforms radically.

Observer-embeddedness in nature implies that the guiding
interests of observation interact with the different kinds of entities to
generate different levels of organization, each reflecting the same hierarchy of
nature.

At this point in the discussion, one might be tempted to simply identify
levels of explanation directly with corresponding levels of organization, given
their reciprocal interdependence. But a second aspect of Salthe's consideration
of observer reflexivity suggests that any such correspondence cannot be simple.
Consider his example of a geologist and biologist formulating the levels of
organization in nature (especially pp. 168f). One easily finds a correspondence
between their hierarchies at the molecular level even though the molecules
involved are quite different. When one examines the levels above that, however,
the phenomena are not comparable. Icicles and turbulence patterns are composed
of molecules, as are organisms, but even though we are studying the "same" level of nature in an important sense, we find they
are not the same "level of
organization."12 The problem shows up
when one starts to connect geological and biological levels of organization.
They should reflect the same ontic levels because nature is unitary, not divided
up into separate geological and biological worlds. But if we collapse the
hierarchies by saying that icicles and organisms are on the same level, we run
into problems. Since both hierarchies are compositional, we say that biological
populations are made of organisms. If icicles are at the same level as organisms
in the same compositional hierarchy, however, then icicles are also components
of biological populations.13 For Salthe, this kind
of confusion is an error of logical type, an indication of absurdity in the same
way that asking about the mass of one's emotions is absurd.

So what are we left with? Biologists and geologists have a few lower levels
which correspond, but we cannot collapse levels of organization studied in the
two disciplines into a single, linearly ordered hierarchy of nature, because we
generate logical absurdities by doing so. This does not imply, in Salthe's view,
that there are multiple natural worlds which cannot be combined. He asserts
clearly his assumption of a unitary hierarchy of nature behind all the studies
of various sciences. For Salthe, what this inability to combine different
formulations of the same ontic hierarchy means is that "[l]evels of
organization can be seen to be the consequence of the observer's being embedded
in "the hierarchy of nature (p. 167). That is, the compositional
hierarchies of biologists and geologists, each reflecting the single hierarchy
of nature from a disciplinary perspective, do not coincide completely because
different kinds of entities (rocks and organisms) exist in nature and
researchers' interests address this complexity. Observer-embeddedness in nature
implies that the guiding interests of observation interact with the different
kinds of entities to generate different levels of organization, each reflecting
the same hierarchy of nature. In short, the patterns of reality (levels of
organization) not only reflect the unity of nature's hierarchy but also the characteristics of observers (researcher interests,
in this instance) interacting with the larger ontic context.

Nothing in this discussion of genetic codes indicates
a total
uniqueness of the questions about function and description.

To summarize, Salthe argues that observer-embeddedness in nature's hierarchy
yields an interdependence between epistemic and ontic hierarchies for
cross-level observation. Difficulties arise in the identification of entities at
lower and higher levels partly because of average rate differences in key
processes at each level. Likewise, one encounters logical difficulties in
combining compositional hierarchies from different sciences even though they
reflect the same hierarchy of creation. Independent of one's final evaluation of
Salthe's proposals as evolutionary biology, his work on hierarchy theory
addresses complications following the acknowledgment of an observer's place in a
hierarchy. His views illustrate the value of distinguishing compositional,
functional, and epistemic levels. Such distinctions become necessary for Salthe
when formulating foundations for evolutionary theory because the scope of the
theory is all life on earth, yielding self-reference. Evidently, the complexity
which attends reflexivity can be managed to some degree with the tools of
hierarchy theory.

Molecular Biology and Genetic Coding

Another important context for exploring relations between epistemic and ontic
hierarchies has received considerable attention: molecular biology and study of
the "genetic code" (e.g., Pattee, 1971, 1973, 1979). The
amount of attention paid to this area generates the advantage of widespread
familiarity with major results, but the attention does not necessarily entail an
appreciation of foundational issues in the field. Along with other scholars,
Pattee (1979) has been attempting to stimulate the molecular biology community
to greater concern for fundamental elements of their work. Specifically, the
empirical successes of molecular biology have, according to Pattee, failed to
stimulate a resolution of certain conceptual debates in the literature which
were present prior to elucidation of mechanisms. Instead, interest seems to have
waned and attention is now focused on the "business as
usual" of building on key discoveries while some conceptual
complexities lie unexplored. For this paper, the issue of interest is that
Pattee employs hierarchical models to address the conceptual problems to which
he points.

Pattee suggests that we first of all need to generalize the notions of
language and description in order to examine interconnections between ontic
levels and descriptive levels in molecular biology. After discussing the
relation between the chemistry of DNA and life, he states in summary:

Life is distinguished from inanimate matter by the co-ordination
of its constraints. The fundamental function of this co-ordination is to allow
alternative descriptions to be translated into alternative actions. The basic
example of this function is the co-ordinated set of macromolecules which
executes the genetic coding. It is useful to think of such co-ordinated
constraints as generalized language structures that classify the detailed
dynamical processes at one level of organization according to their importance
for function at a higher level. In this sense, co-ordinated constraints,
language structures, alternative descriptions and hierarchical controls are
inseparably related concepts. (1971, p. 171)

Since the sequences of bases are physico-chemically
"indeterminate," DNA strands and associated macromolecules
bear information ("alternative descriptions"), thus
permitting genetic patterns to serve as constraints (designs) for cellular
functioning.14 The distinction here between
physico-chemical processes and information is central to his claim. As Pattee
states, "the relation between the structural [in my terms,
compositional] and descriptive levels is the central problem that must be solved
to have a theory of hierarchical control" (1973, p. 136, emphasis
deleted).

Summarizing Pattee's views in the vocabulary employed here, the topic of
interest is the interface between molecular and cellular levels of a biological
composition hierarchy. Conceptualizing genetic codes and information as "generalized language structures" or descriptions ties in
epistemic hierarchies at this same boundary between levels. That is, he presents
biological information as one level of an epistemic (informational)
hierarchy.15 In my elaboration of Pattee's
discussion, hereditary mechanisms are examples of compositional and epistemic
hierarchies entwining at an interlevel interface. So his critique of molecular
biology clearly distinguishes ontic and informational levels while confronting
basic conceptual issues. Without presenting a full analysis of genetic codes,
one can see that Pattee's foundational questions in molecular biology are more
easily formulated once one has distinguished ontic and epistemic levels.
Clarifying, extending, or critiquing Pattee's analysis requires even further
elaboration of levels notions.

The purpose of hierarchical models is to disclose some
of the
intricate pattern of epistemic-ontic interaction in a "participative
ontology."

One can extract several lessons from Pattee's discussion of molecular
genetics.16First, the empirical grounding of the
area helps focus important questions, but data alone do not resolve questions
about hierarchical interrelations. Pattee's concern about scientists focusing on
mechanisms to the exclusion of conceptual fundamentals makes this point.
Although empirical and philosophical questions are intimately intertwined in
this context, it does not seem that we have a case of "naturalization" of fundamental issues in genetics,
popularized statements to the contrary
notwithstanding.17 Thus, simply going back to the
lab will not make these questions go away. Second, I suggest that formulations
of these issues via hierarchical models is more fruitful than attempts to avoid
levels concepts. By restricting attention to "information,"
for example, instead of dealing with Pattee's notion of "generalized
language structure" or informational levels, one might claim that
hierarchy is irrelevant to genetic codes or biological information. However,
such a move merely buries the same issues in the definition of "information." We can still ask about the relationships
between genetic and linguistic information, for example, by suggesting that
sorting out that relationship is important for adequate definitions. As a final
lesson, I suggest that nothing in this discussion of genetic codes indicates a
total uniqueness of the questions about function and description. One might
anticipate that elaborations of hierarchical models in molecular genetics could
be generalized in some form to apply to other domains of inquiry. For example,
there may be fruitful parallels between the interlevel interface of genetic
codes and traditional condundrums surrounding mind-brain or individual-society
relations.18 In short, Pattee's work illustrates
contributions of hierarchy models at a specific interlevel interface.

Philosophy of Science & Epistemology

Salthe and Pattee's work on hierarchy theory addresses epistemology as
necessary for advancing our understanding of levels. Arbib and Hesse (1986), on
the other hand, find levels notions necessary for their project of developing an
epistemology. Their contributions to the present exploration of ontic-epistemic
relations in hierarchy theory center on questions about the ontic status of
epistemic hierarchies. Also, they deal explicitly with knowledge of spiritual
domains. So a brief excursion into their work can illustrate another way
hierarchy theory might benefit dialogue between scientists and religionists.

Their project extends schema theory from roots in cognitive science and
Piaget to the development of an epistemology which can address both scientific
and religious knowledge.19 Moreover, in their
elaboration of schema theory Arbib and Hesse maintain a consistent awareness of
hierarchical patterns (although they do not present a systematic hierarchy
theory).

We need a multilevel description of the human being. Schema
theory, as it develops, is to provide an ever more appropriate mental
vocabulary, while neural processes provide the mechanism for schema storage and
dynamics. This is both more and less than reductionism. In some sense,
everything in human behavior or society is mediated by neural firing and other
physicochemical processes. And yet, there is no useful sense in which our
analysis of human beings can be conducted exclusively at that level. We have
many different levels of description, including neural, mental, and social, and
we find ways of illuminating any particular level of discourse by placing it
within a higher level context and by seeking lower level mechanisms. In this
way, we see how to think coherently of the neural and the social levels as
placing constraints on the schema level of analysis without claiming that any
level is the one true level at which we should conduct all discussion. (pp. 14f)

Although their phrasing in this passage might lend itself to
an interpretation restricted to epistemic levels, Arbib and Hesse are clear that
patterns of reality are also at stake: "we in fact advocate a
permissiveness with respect to ontology: there are all manner of levels of
reality."20

Within the background of these general comments, Arbib and Hesse address the
ontic status of epistemic hierarchies: In what sense is language or scientific
theory real? They start by accepting spatio-temporal reality as unproblematic in
that members of our culture readily acknowledge that the physical world is "real." On the other hand, the reality status of values,
rational truths, symbol systems, ideologies, and God is questioned (pp.
2-5; cf., pp. 58-62, 84). (Interestingly in this context,
questions regarding the ontic status of logic are explicity avoided, pp. 59f.)
Nevertheless, in their view knowledge systems are real at least in the sense
that our theories, for example, impact physical reality through human action.
For these authors, the clearest case of this process is technology: scientific
knowledge clearly impacts the physical world through application in technology,
and knowledge has to be real in some sense to influence spatio-temporal
reality.21 In short, the interaction of epistemic
levels with physical reality (via technology) demonstrates something of the
ontic status of epistemic phenomena (e.g., scientific theory).

For the present discussion, my main interest is their broader principles for
studying the ways in which knowledge systems are "real."
First, they assert that hierarchical patterns of description are necessary to
elaborate an epistemology adequate to deal with both scientific and religious
knowledge. Then, while assuming unspecified hierarchical patterns of reality,
they also note that (a) language, scientific knowledge, and other knowledge
systems (which have hierarchic form themselves) are real in a different manner
than is physical reality, but that (b) knowledge systems can change physical
reality (with technology being the main example of how this happens). Thus, a
major principle in Arbib and Hesse's approach is that when epistemic systems
impact physical reality, the impact gives us important clues about the ontic
status (type of reality) of the epistemic
systems.22

When examining the reality of spiritual knowledge systems,
we
can look, in various senses,
to the consequences of spiritual knowledge for
spiritual (and physical and social and cognitive) reality.

Arbib and Hesse's argument presents a clear analogy to Pattee's claim that
the functional consequences of genetic information in the physical system of a
cell reflect the impact of a "generalized language
structure." In both cases, information (in genes or theory) strongly
influences physical reality (via organism functioning or human technology)
through known mechanisms (cellular decoding systems and technology). Similarly,
Salthe's views on observer reflexivity portray observation processes as
inextricably intertwined with levels of organization, observer actions, and
observer interests. These facets of observer epistemology actually shape
reality. In this sense, descriptive levels are not simply shortcomings of human
capacity which limit the extent of human
knowledge.23 Despite widely diverse foci of
discussion, these authors all suggest a "participative
ontology" of some kind where epistemic issues are intimately
intertwined with ontic processes. In this kind of "constructivist" view, reality independent of an observer
is, in principle, not identical to reality including
observers.24 The purpose of hierarchical models in
this context is to disclose some of the intricate pattern of epistemic-ontic
interaction in a "participative ontology." Once again,
whether or not we want to accept a constructivist viewpoint, I want to point out
the value of levels notions in explicating what the concepts mean. In fact, it
seems to me that hierarchical models are necessary either to support or to
refute constructivist theories like those examined here.

One aspect of Arbib and Hesse's work covers topics not addressed by the
authors focusing on biological topics: the interconnections of social and
spiritual realities with a hierarchy of nature. The full range of biological,
mental, and social levels are considered minimal context for an epistemic
framework adequate for addressing spiritual reality. How, then, can we apply
their principle for the "reality" of epistemic systems noted
above? When examining the reality of spiritual knowledge systems, we can look,
in various senses, to the consequences of spiritual knowledge for spiritual (and
physical and social and cognitive) reality.22
Consider also how the broad scope of their model raises questions about
reflexive features of Arbib and Hesse's program (paralleling Salthe's model of
observation). Once one addresses spiritual activity in addition to cognitive and
social activity, the question comes up regarding the relations of spiritual
knowledge to the scholarly enterprise. Unless one posits a complete autonomy of
scholarship from spirituality, another loop of self-reference arises when
considering an epistemology of spiritual
reality.25 In light of these points and those in
previous paragraphs, it seems clear to me that Arbib and Hesse's levels
conceptualizations will continue to distinguish and interrelate epistemic and
ontic hierarchies (as well as challenging us with important issues). Once again,
the distinctions highlighted here can prove beneficial for topics related to
science-religion dialogue.

In our age of technological science,
we are well accustomed to a
variety of tools which extend the ranges of our senses...
there is no
debate about the "reality" of invisible wavelengths of
electromagnetic radiation.

In short, Arbib and Hesse do not present a systematic hierarchy theory, but
their theory of knowledge does depend explicitly on levels ideas to conceptually
ground their approach. This epistemology project stimulates important questions
by going beyond scientific knowledge to include other forms of social and
religious knowledge. Overall, careful examination of Arbib and Hesse's work
hints at an intricate interweaving of hierarchy notions with the complexities of
an epistemology of spiritual and scientific realities.

Summary

I started this paper by pointing out that
"levels of
explanation" and related ideas play important roles in many
discussions of relationships between science and religion. That importance alone
justifies attempts to work out more detailed understanding of these notions. By
reviewing selections from literature on hierarchy theory and epistemology, I
attempted to show that there are available resources available for clarifying
levels concepts. One basic contribution was offered in the distinction between
epistemic, compositional, and functional levels. Complexities associated with
observer reflexivity, interlevel boundaries, and spiritual knowledge were
clarified by distinguishing these different kinds of hierarchies. Rather than
providing complete resolutions to the complexities encountered, this paper
invites scholars interested in science-religion dialogue to continue the
elaboration of available hierarchical models. I believe the work required will
continue to be rewarded, and that available literature demonstrates the promise
of levels notions for further grounding of religion and science dialogue.

The literature on hierarchy theory is certainly not the only resource we can
draw upon in expanding our understanding of levels concepts. Additional
resources in philosophy and systems theory, for example, are also well worth
exploring. This paper does not attempt to review all valuable literature. There
is, however, at least one major point which has not received adequate attention.
I claim that elaborating our levels concepts will contribute to the dialogue
between science and religion. With the introduction provided in this paper, I
can turn more directly to the task of further illustrating these contributions
in "Levels of Explanation: Part II.(1991)"

This paper is a revision of a portion of a paper presented at
the 1988 ASA annual convention in Malibu, California. I want to acknowledge the
contributions of colleagues to this paper. Vaden House provided critique and
conversation which significantly strengthened both my thinking and my writing. I
can no longer distinguish at this point between lessons learned in conversation
with him from learning gained elsewhere. For repeated encouragement and material
support, I thank Harry Cook and also Hank Bestman. Comments by several people at
the 1988 conference and by several reviewers were stimulating as well as
encouraging.

NOTES

1The designation
"hierarchy
theory" has not acheived consensual acceptance, but it is a convenient
designation for a multidisciplinary concerns tied together by questions
involving hierarchies of levels (e.g., Pattee, 1973). For definitional issues,
see note 2.

There are many other resources besides levels ideas to draw upon
in sorting out complex systems. For a popularized overview of various facets of
complexity in science, see Davies, 1988.

2See, for example, Ayala, 1974;
Barbour, 1966; Bunge, 1956; Grene, 1967; Pattee, 1973. No complete definition of
levels or hierarchy is attempted because there is no widely accepted formulation
to date despite substantive work in the area (e.g., Bunge, 1977). Generally,
definitions of levels involve specifying units of analysis which characterize
each level and definitions of hierarchies require an ordering among levels. For
the present discussion, the common practice of accepting implicit definitions by
use of example is adopted rather than the common alternative of stating precise
but inadequate working definitions. Substantiating selected definitions is a
worthwhile project which is beyond the scope of this paper.

The epistemic-ontic distinction highlighted here does not imply
that one can somehow separate or isolate reality from knowing. Rather, one
inherently refers to inseparable aspects of complex processes. Likewise,
inseparability does not imply that the distinction is meaningless.

3See, for example, MacKay, 1982. I am
not claiming here that MacKay distinguishes between ontic and epistemic levels.
The nature of functions in comparison to entities is the question at issue, and
some thinkers want to be able to assert the reality of functions as different
from the reality of entities (e.g., Barbour, 1966; Hart, 1984). Making the
distinction does not beg the question, but it does aid in formulating both the
question and the associated debate.

5For this paper, I address
evolutionary theory per se and do not consider evolutionism;
i.e., issues following from such theory used as a basis for a myth of origins.
Levels notions do not arbitrate directly between viewpoints on creation and
evolution. Salthe's work is evolutionary while van der Meer (1989) is developing
a hierarchical creationist model. It seems to me that levels notions are
fundamental enough to fit with a variety of world views (though not all).

6Salthe, 1985. Although Salthe's
approach is explicitly non-reductionist in some senses, it is not merely
biologists who prefer "reductionist" approaches who might
disagree with Salthe's proposals (cf., Williams, 1985). Marjorie Grene (1972),
for example, argues for hierarchical models but takes issue with the general
form of theoretical synthesis of evolution rooted in the hierarchies of a
systems theory. My point in examining Salthe's work is to explore his extension
of hierarchy theory to the interactions of epistemic and ontic hierarchies.
Debating specific positions on reduction-emergence, evolutionary biology, or the
nature of genetic information are related to these aims, but these debates also
beyond the scope of this paper.

It is also helpful to point out that Salthe's attempts to deal
with reflexivity do not imply a disdain for non-reflexive theorizing (see
especially chap. 6). As I read him, he sees his effort as a generalization
attempt which addresses a complexity that was ignored for the sake of
(necessary) simplification in the early stages of theory construction. In that
sense, perhaps, the development of reflexive evolutionary theory can be seen as
analogous to mechanics which takes friction into account. For more general
background on reflexivity issues, see Bartlett & Suber (1987).

7It is helpful to note that rate
differentials do not need to be exhaustive for his point to carry weight, they
simply need to dominate the major processes of respective levels. See Allen
& Starr (1982) for a discussion of similar points in biological ecology
theory. In discussing Salthe's views, the distinction between entities and
processes need not be strong because he sees the two languages as
interchangeable to a large degree.

Discussions of process rates are pursued by Salthe to address the
more central notion of transitivity of effects across multiple levels in a
hierarchy. His broader concerns, although of interest, are not addressed here
due to space limitations.

8I emphasize direct perception to make
the point about rate differentials, not to deny that technological developments
expand the range of human observation. In fact, the technology of observation is
of interest in the present context and is mentioned below.

9It bears repeating that Salthe's
point emphasizes the average rate differential between levels. Thus instances of
direct interaction between entities of widely divergent levels and process rates
are not counter-instances. The sun interacts directly with many organisms in
photosynthesis and sunburn, but we still perceive our star as a constant part of
the environment and its light as a constant flux of energy instead of as a
waveform or a stream of particles (despite the theoretical perspectives gained
by twentieth-century physics).

Also, there is nothing especially significant solely in the fact
that rate differentials render the perception of entities and processes at
different levels more difficult. In our age of technological science, we are
well accustomed to a variety of tools which extend the ranges of our senses. A
simple case is illustrated by the fact that, at this stage of scientific
understanding, there is no debate about the "reality" of
invisible wavelengths of electromagnetic radiation. Salthe's emphasis on the
interaction of epistemic and ontic levels in rate differentials is better
illustrated by debates about theoretical notions which are sometimes interpreted
instrumentally and sometimes realistically. For example, the kinds of reality
represented by species or ecosystems is not currently a matter of consensus
among scholars. In debates about whether certain scientific constructs are about
"real" objects or processes, reflexive interactions of human
observers and other levels involve epistemic hierarchies and compositional
hierarchies in mutual influence. In debates of this kind, definitional and
methodological issues highlight an interdependence between epistemic and ontic
hierarchies. Thus, as I read Salthe, his views amount to claiming that when we
debate basic definitions, levels of explanation and levels of organization are
equally basic in science.

This point can be illustrated by two questions, the first
emphasizing epistemology and the second ontology, but each one depending equally
on the other. (1) What perspectives are appropriate to study X (since Xs are
this kind of thing)? (2) What kind of thing is X really, given our data and
observations of it and related phenomena? In other words, once we are clear on
the kind of reality a certain phenomenon reflects, we know best how to study it,
and when we are clear on the ways to study a phenomenon, we can best determine
what kind of reality the phenomenon reflects. This interdependence is
particularly clear when methodological and definitional debates surface.

Just as self-proclaimed reductionists or materialists
employ
hierarchy theory as effectively as do "emergentists"
...so
the use of hierarchical models will probably not,
in and of itself, prejudge
conclusions about other, related questions.

10Salthe discusses the emergence of
new levels between old ones and higher levels above old ones. Pursuing those
concerns would take this discussion too far afield, however interesting and
important it is.

11See Arbib and Hesse, 1986, on
technology as one mechanism for knowledge generating ontic consequences. Their
views on this point are briefly noted below.

Most coupling processes do not reflect solely the differential
rates of processes, though in Salthe's work rates are emphasized. Coupling and
decoupling processes involve many facets. For the present discussion process
rates serve well as a feature of activity in our world which concretizes some
aspects of interlevel interactions.

12In Salthe's terms, these discussions
are about a "rank" of nature as a class, and about the
relations between levels of generality, functional levels, and cognitive
processes like labeling and attention. I have simplified the discussion here
because of space constraints. For more detail, see chapter 6 of Salthe in
particular.

13This specific example can be
addressed by changing the structure of hierarchies from simple linear orderings
of levels to partial orderings of levels, yielding a "branched" hierarchy with a common trunk and geological and
biological "forks" (cf., Salthe chaps. 3 & 6). This form
of complexity fits with Salthe's general thesis, but it does not address other
cases where there are no levels in common between two related hierarchies. The
more complicated examples were not used in this discussion due to space
limitations. For more detail on these issues in Salthe, see his discussions of
relationships between geneological and ecological hierarchies, especially his
chapter 7.

14Even more broadly, the set of
related notions necessary for coherent and comprehensive study of genetic codes
includes information, function, meaning, and structure (cf. Grene, 1967; MacKay,
1969; Pattee, 1979).

15In his 1979 paper, Pattee elaborates
his views on relations between biological information, structure, and language,
specifically arguing for complementary relations reflecting (generalized)
measurement processes. The various complementarities are not synthesized into an
overarching hierarchy as far as I can tell. He does, however, emphasize the
epistemological nature of information-structure complementarity and he does
distinguish, in passing, levels of complexity of information (e.g., pp. 218f).
While his work in these and other papers provides a large amount of material to
help ground and develop hierarchy models, I avoid greater detail here to
conserve space. For discussion of the related complex of issues, see Bennett's
comment on Pattee's 1979 paper, Pattee, 1978, and MacKay, 1969. Consideration of
the relation between information and biological function is a further direction
for elaborating here.

16Of course, many important questions
are left unmentioned here. Many readers of this journal are probably aware, for
example, that sources of information in genetic systems were explored in a
recent conference sponsored by ASA's Committee for Integrity in Science
Education (see Walter Hearn's description in the August/September 1988 issue of
the Newsletter of the ASA/CSCA, 30(4), pp. 1-2).
Since the papers from this conference are not being circulated pending
publication, we will have to wait to benefit from the struggles there for
additional detail on relationships between information, function, and
biochemistry. For the present discussion, however, it is worth noting that
disagreements regarding "physical discontinuity" or "a seamless cause-and-effect continuum" (see Walt Hearn's
description) can most likely be argued on both sides with the support of
hierarchy theory. Just as self-proclaimed reductionists or materialists employ
hierarchy theory as effectively as do "emergentists" (e.g.,
Bunge, 1977; Campbell, 1974; Glenn, 1988; Wimsatt, 1986), so the use of
hierarchical models will probably not, in and of itself, prejudge conclusions
about other related questions.

Instead, my expectation is that the continuity-discontinuity
disagreement may in fact be made more constructive through clearer formulation
of relevant hierarchies. My point about the fertility of hierarchy theory and
the importance of informational hierarchies does not presume a resolution to
continuity-discontinuity debates, though implications of my stance may the raise
stakes of the discussion through a transformation of the questions. Better
understanding of sources of information content in the genetic code cannot but
benefit the discussion (by displacing controversy about speculative models, for
example), but it will probably not resolve longstanding controversies.

17Naturalizing philosophical questions
takes place when intellectual debate over questions is replaced by, or made moot
by, empirical findings. From a naive point of view, an assumption of exhaustive
naturalization of philosophy sometimes seems to be made by those who see
philosophy as irrelevant to science.

18See Pattee, 1978; cf. Davies, 1988.
The central strategy of hierarchy models is twofold: (a) to distinguish
phenomena at different levels, and (b) to synthesize a set of such distinctions
into a series of levels, a hierarchy. Both of these principles serve the central
purpose of levels models: to adequately recognize and understand complexity. So
the interest of Pattee and others in relating physical, biological, and social
phenomena in hierarchy models clearly reflects their understanding of the
cosmos. It is not merely an afterthought of grandiose theorising.

19Arbib and Hesse define schema as a
"`unit of representation' of a person's world,"
including both synchronic and diachronic patterns of change (pp. 13f; cf. p.
61).

20Arbib & Hesse, 1986, p. 65. The
details of relations between ontic levels and levels of description are
purposely not specified in their presentation, however. Arbib & Hesse do
describe their stance in general terms as a constructivism or perspectivism,
distinguishing their view from "strong versions" of
scientific realism (cf. pp. 10 & 182, passim). They also
indicate that they consider their epistemology is compatible with many, but not
all, ontologies. For the sake of clarity, these authors also note that the
emphasis on levels originated with Hesse.

21The impact of scientific theory on
our world via technology is only one form of epistemic influence. To prevent
confusion, one would eventually need to distinguish this kind of influence
(knowledge of physical reality impacting physical reality through human action)
from, for example, self-fulfilling prophecy (social knowledge impacting on
social reality; see, e.g., Watzlawick, 1984) or the effects of prayer (human
action rooted in spiritual knowledge?) mediated through God's actions (spiritual
reality?; see also note 22).

22A central point to sort out while
exploring the ontic consequences of epistemic processes is the relationships
among various levels and domains. For example, consider the "prayer-test controversy" which revolved around whether the
prayers of Christians ought to result in empirically demonstrable consequences
in physical domains (see Myers, 1978). Before one could test the efficacy of
prayer, a well-developed theory (theology) would be required to predict what
kinds of effects would be anticipated in various domains and at various levels: physical, biological, psychosocial, spiritual, etc
.Likewise, an auxiliary theory of measurement would be necessary to indicate
what observation processes would be required. Perhaps the prime question for
scientists is whether any scientific approach can mesh with any subset of these
questions. In effect, asking such questions is a natural consequence of a
unified epistemology able to bridge spiritual and physical reality. Although we
may not have, at present, fully formulated responses to these questions, my
classroom experience attests to the clear relevance of these issues to the lives
of many students (not to mention everybody else)! In my mind, the fruitfulness
of Arbib and Hesse's goal is clear. Thus the tools we have available to move
toward that goal, such as hierarchy theory, are of value.

23One strategy for accounting for
empirical levels patterns is an epistemic pluralism (multiple levels of
concepts) combined with a unileveled reality which, in a strong form of the
thesis, sees levels as distortion due to the limitations of human cognition.
This kind of approach can support either an instrumentalism which avoids ontic
questions or perhaps a complex view of human fallibility. Although a realist
approach certainly would need to develop a theory of error in human knowledge of
hierarchies, realists would also require some form of validity in such
knowledge. All I want to assert at this point is that I find it highly
implausible to attribute all forms of hierarchy in the world to cognitive
distortion.

I also assume in this discussion that the ontic impacts of
mistaken understanding and valid understanding are distinguishable in some
sense. From this point arises my reservations about instrumentalism.

24I make no attempt here to
distinguish among various schools of thought using the label, nor to
differentiate between "constructionism" and "constructivism." Arbib and Hesse use the term for their
views and important parallels drawn with the other authors discussed here
reflect the same general stance in my view. For overviews of a few forms of
constructionism, see Watzlawick, 1984.

25I am the first to admit complexities
associated with the relations between scholarship and faith. I am not trying to
be glib, only to point out important concerns. It does not seem reasonable to
anticipate easy answers for or against patterns of spiritual self-reference in
scholarship. Arbib and Hesse's position stimulates such discussions as does the
work of many other authors (e.g., Woltersdorff, 1984; MacKay, 1979; Mavrodes,
1977; Heie and Wolfe, 1987). My central point at this time is simply that
elaboration of our levels notions is important to do justice to this issue, as
well as others.

In the examples examined in this paper, obvious connections exist
between evolution, molecular biology, and our understandings of creation.
Rational and spiritual self-reference emerge behind every corner in such
discussions. What Arbib and Hesse's epistemology offers is a framework within
which to explore interrelations among specific theories of science and theology.
Although the general case may permit the luxury of avoiding some details of
levels structures, my clear sense is that elaborate hierarchy models are
required for adequately addressing specific questions.

Grene, M. (1967/1974). Biology and the problem of levels of
reality. In M. Grene, The Understanding of Nature: Essays in the
Philosophy of Biology (vol. 23 of the Boston Studies in the Philosophy
of Science; pp. 35-52). Dordrecht, Holland: D. Reidel. (reprinted from The New
Scholasticism, 41, 94-123).

Grene, M. (1972/1974). Aristotle and modern biology. In M.
Grene, The Understanding of Nature: Essays in the Philosophy of
Biology.